Although new joining processes, such as bonding or punch riveting, are coming increasingly into play, welding is and will remain a key technology in the production of special vehicles. This is certainly true for Rosenbauer International AG, the global player among fire-fighting equipment suppliers. Restricted space, ever more complex components, the increased use of aluminum and stainless steel, as well as sustained cost pressures all demand higher-performance welding technology systems than in the past. The TPS/i MIG/MAG welding platform from Fronius meets these demands and helps to satisfy the needs of today and tomorrow, as a pleased Rosenbauer has discovered after months of practical testing.
Right from when the brand new MIG/MAG power source from Fronius was first tested, it showed what it was capable of meeting these demands. In a test conforming to the European standard, EN 287-1 or EN 9606-1 (10 mm steel plate, a7 vertical-up), it was directly compared with current systems from other manufacturers.
“For our colleagues, the TPS/i from Fronius was clearly the best of the bunch,” reports Michael Jungwirth, welding specialist at Rosenbauer International AG. “Simply the noise of the arc and just a few meters of weld seam were enough to make it clear that this has taken us to a completely new level of welding quality.”
The decision to purchase the first TPS/i was made just as quickly. Since then, the new device has been put through its paces and used across the widest variety of areas in prefabrication. In doing so, it has had to function in all welding positions while processing steel, aluminum and stainless steel.
MIG welding replaces TIG
The weld seams to be generated at Rosenbauer are mostly visible seams where particularly high demands are placed on the surface appearance. In the past, welders often used the TIG process to do this. Though good for producing very neat weld seams, it requires some practice and only allows a low welding speed.
“The TPS/i will enable us to weld such visible weld seams quickly and cleanly in the future,” explains a pleased Walter Wolfesberger, head of prefabrication at Rosenbauer International AG. “This eliminates the time-consuming process of changing devices or converting the power source.”
A critical role is played by the LSC (Low Spatter Control) characteristic, which was unveiled with the TPS/i. The basic algorithm uses the extremely high computing power and control precision to provide the welder with an even more stable arc with minimum spatter ejection.
Changing position without impacting quality
“This enables us not only to create a visually immaculate weld seam, but also to tackle difficult changes in position,” says Jungwirth. “For example, thanks to the LSC Universal dip transfer arc characteristic, the transition between overhead and gravity position welding no longer presents a problem.”
This property is in demand if Rosenbauer needs to extend the C-profile vehicle frame made from formed QSTA500 9-mm fine-grained structural steel with a weld seam created in an (out-of-position) overhead, then vertical-up and then gravity position.
“Targeted heat input is essential here in order to reliably secure the material and thereby to ensure the required stability of the construction,” advises the Rosenbauer welding specialist. “The TPS/i can even take this challenge completely in its stride.”
Penetration stabilizer for even more safety
Additional safety when carrying out such challenging welding work is provided by the penetration stabilizer, available for the first time with the TPS/i. When activated, it ensures a constant penetration even in the event of external interference, such as stick out variations. This has a particularly positive effect on fillet welds that are to be welded in the vertical-up position with an oscillating motion, but also on workpieces that are difficult to access.
Most of the time, welders at Rosenbauer only need to weld very short weld seams. As such, their area of work includes producing protective grids for vehicle windows that are made from 8-mm stainless steel wire. The wires have to be tacked in place at the crossover points.
“Recently we have used only the TPS/i for such delicate welding work because it is simply the device with the best ignition properties,” explains the head of prefabrication.
High weld seam quality from the very first millimeter
Even when welding thin aluminum sheets, such as those regularly processed at Rosenbauer, ideal ignition properties and a controlled, stable arc are essential for adhering to the necessary high standards of quality.
“Initial tests with aluminum have shown that the new PMC pulsed arc characteristic already exhibits significant advantages when welding aluminum, even in the default setting. These benefits are also present with the 1- to 3-mm-thick aluminum sheets that are heavily used by us,” says Jungwirth. “Thanks to the availability of the PullMig welding torch, we can now weld low-alloy sheets, aluminum and stainless steel with just one device and without any need for lengthy conversion work.”
After completing the trials, Rosenbauer now plans to continue using the TPS/i flexibly and across the board. The frequent changes of location, welding task and operator that all come with this will be no inconvenience at all thanks to the exemplary handling.
Wolfesberger concludes: “After taking just a few minutes to get used to the tool, our welders are ready to go with the TPS/i.” This factor is also linked to the new graphic user interface, as his colleague explains: “The welding circuit resistance can be adjusted in no time at all. In fact, as a welder, you can’t really go wrong.”
Easy handling, right down to the details
The specialists are unanimous in crediting the new user interface and many other details with making the device extremely easy to use. This includes the uniform color coding of wearing parts, which helps to accurately identify suitable or corresponding parts in the event of any changes.
“We don’t have anywhere near as many issues as before,” says Jungwirth. He is also enthusiastic about the cooling capacity of the new system. “Whereas previously there was the risk of burns, today we have surprised faces when people realize that the welding torch can be handled safely without gloves after a very short time,” he explains.
Yet another example of the excellent handling is the servicing and updating of the power source software, which has been made much easier through the networking ability of the new devices. As a result, the equipment can be centrally managed and updated via the network. “We are now at the point where we can closely assess the high level of potential offered here to simplify our documentation and quality control processes,” reveals Wolfesberger.
Even if Rosenbauer has still not gotten round to exploiting or testing out all of the functions and applications of the new power source, the head of department’s conclusion is already unequivocal: “With the TPS/i, Fronius is leading us into a new, previously unattainable dimension in terms of handling, arc stability and arc control.”